#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>
#include<string.h>

int main() {
    int hash[501] = { 0 };
    char arr[501] = { 0 };
    gets(arr);
    int sz = strlen(arr);
    int i = 0;
    int count = 0;
    for (i = 0; i < sz; i++)
    {
        hash[arr[i]]++;
    }
    for (i = 0; i <= 127; i++)
    {
        if (hash[i] > 0)
        {
            count++;
        }
    }
    printf("%d", count);
    return 0;
}

int majorityElement(int* nums, int numsSize) {
    int count = 1;
    int i = 0;
    int num = nums[0];
    for (i = 1; i < numsSize; i++)
    {
        if (nums[i] == num)
        {
            count++;
        }
        else
        {
            count--;
            if (count < 0)
            {
                count = 0;
                num = nums[i];
            }
        }
    }
    return num;
}